Combustion of Alcohol Investigation
Aim: To burn a range of alcohols separately in air and measure the energy changes that take place.
Background Knowledge: Combustion is a chemical reaction between substances, usually including oxygen and usually accompanied by the generation of heat and light in the form of flame. The rate or speed at which the reactants combine is high, in part because of the nature of the chemical reaction itself and in part because more energy is generated than can escape into the surrounding medium, with the result that the temperature of the reactants is raised to accelerate the reaction even more Flames have a definable composition and a complex structure; they are said to be multiform and are capable of existing at quite low temperatures, as well as at extremely high temperatures. The emission of light in the flame results from the presence of excited particles and, usually, of charged atoms and molecules and of electrons.
Combustion is one of the most important classes of chemical reaction, is often considered a climax phenomenon in the oxidation of certain types of substances. Although most flames have regions where reduction reactions are important, combustion is primarily the combining of combustible material with oxygen. The chemical processes in combustion are most commonly initiated by such factors as heat, light, and sparks. As the combustible materials achieve the ignition temperature specific to the materials and the ambient pressure, the combustion reaction begins. The combustion spreads from the ignition source to the adjacent layer of gas mixture; in turn, each point of the burning layer serves as an ignition source for the next adjacent layer, and so on. Combustion terminates when equilibrium is achieved between the total heat energies of the reactants and the total heat energies of the products.
Combustion may also emit light energy, mostly in the infrared portion of the spectrum. The light emitted by a flame arises from the presence of particles in electronically excited states and from ions, radicals, and electrons.
An alcohol is a series of organic homologous compounds, with the general formula Cn H n + 1OH´. Alcohol's react with oxygen in the air to form water and carbon dioxide. The reaction that is involved in burning alcohols is exothermic because heat is given out. Form this reason the reactant energy is higher than that of the product.
An alcohol is a series of organic homologous compounds, with the general formula Cn H n + 1OH´. Alcohol's react with oxygen in the air to form water and carbon dioxide.
The reaction that is involved in burning alcohols is exothermic because heat is given out. Form this reason the reactant energy is higher than that of the product.
Prediction:
I predict that the bigger the molecule of alcohol the higher the amount of energy given out will be. This is because the bigger the molecule the higher number of bonds needed to break and make. Therefore, you would need a higher amount of energy to break them apart. For example, Ethanol has the formula C2H5OH. In this, there are five C-H bonds, one C-O, 1 C-C, 1O-H. To break up each of these bonds you will require a certain amount of energy (this is shown on my energy diagram). Altogether, you will need 4728Kj of energy to break up an Ethanol molecule. Then the molecules regroup to form Carbon Dioxide and water molecules. When creating bonds molecules must give out energy. When creating Carbon Dioxide a high amount of energy is given off. In Ethanol 3220Kj of energy are given out when creating 2CO2 molecules. This gives a total of 6004Kj of energy given off. One C=O has 805Kj of energy. Therefore, this produces most of the energy given off. Therefore, the higher the amount of Carbon atoms in each molecule the more CO2 can be made. As the alcohol molecule gets bigger, the percentage of carbon contained in it also increases. This means that as the molecule gets bigger so does the amount of energy given off. For example Methanol is a small alcohol molecule and contains one carbon molecule. Whereas Pentanol contains five carbons. This means that Pentanol can make more Carbon Dioxide bonds therefore given off more energy. Below is a prediction of what I think the graph will look like.
Aim: To burn a range of alcohols separately in air and measure the energy changes that take place.
Background Knowledge: Combustion is a chemical reaction between substances, usually including oxygen and usually accompanied by the generation of heat and light in the form of flame. The rate or speed at which the reactants combine is high, in part because of the nature of the chemical reaction itself and in part because more energy is generated than can escape into the surrounding medium, with the result that the temperature of the reactants is raised to accelerate the reaction even more Flames have a definable composition and a complex structure; they are said to be multiform and are capable of existing at quite low temperatures, as well as at extremely high temperatures. The emission of light in the flame results from the presence of excited particles and, usually, of charged atoms and molecules and of electrons.
Combustion is one of the most important classes of chemical reaction, is often considered a climax phenomenon in the oxidation of certain types of substances. Although most flames have regions where reduction reactions are important, combustion is primarily the combining of combustible material with oxygen. The chemical processes in combustion are most commonly initiated by such factors as heat, light, and sparks. As the combustible materials achieve the ignition temperature specific to the materials and the ambient pressure, the combustion reaction begins. The combustion spreads from the ignition source to the adjacent layer of gas mixture; in turn, each point of the burning layer serves as an ignition source for the next adjacent layer, and so on. Combustion terminates when equilibrium is achieved between the total heat energies of the reactants and the total heat energies of the products.
Combustion may also emit light energy, mostly in the infrared portion of the spectrum. The light emitted by a flame arises from the presence of particles in electronically excited states and from ions, radicals, and electrons.
An alcohol is a series of organic homologous compounds, with the general formula Cn H n + 1OH´. Alcohol's react with oxygen in the air to form water and carbon dioxide. The reaction that is involved in burning alcohols is exothermic because heat is given out. Form this reason the reactant energy is higher than that of the product.
An alcohol is a series of organic homologous compounds, with the general formula Cn H n + 1OH´. Alcohol's react with oxygen in the air to form water and carbon dioxide.
The reaction that is involved in burning alcohols is exothermic because heat is given out. Form this reason the reactant energy is higher than that of the product.
Prediction:
I predict that the bigger the molecule of alcohol the higher the amount of energy given out will be. This is because the bigger the molecule the higher number of bonds needed to break and make. Therefore, you would need a higher amount of energy to break them apart. For example, Ethanol has the formula C2H5OH. In this, there are five C-H bonds, one C-O, 1 C-C, 1O-H. To break up each of these bonds you will require a certain amount of energy (this is shown on my energy diagram). Altogether, you will need 4728Kj of energy to break up an Ethanol molecule. Then the molecules regroup to form Carbon Dioxide and water molecules. When creating bonds molecules must give out energy. When creating Carbon Dioxide a high amount of energy is given off. In Ethanol 3220Kj of energy are given out when creating 2CO2 molecules. This gives a total of 6004Kj of energy given off. One C=O has 805Kj of energy. Therefore, this produces most of the energy given off. Therefore, the higher the amount of Carbon atoms in each molecule the more CO2 can be made. As the alcohol molecule gets bigger, the percentage of carbon contained in it also increases. This means that as the molecule gets bigger so does the amount of energy given off. For example Methanol is a small alcohol molecule and contains one carbon molecule. Whereas Pentanol contains five carbons. This means that Pentanol can make more Carbon Dioxide bonds therefore given off more energy. Below is a prediction of what I think the graph will look like.
